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Administration and Provisioning
8-42 Issue 3 June 2001
OC-3 and OC-12 Ring Cross-Connection
Provisioning 8
For every DS1, VT1.5, STS-1, STS-3C or DS3 transported through a ring
network, a cross-connection is needed in every NE (node) on the ring. A "drop"
cross-connection is needed at the nodes where service enters or exits the ring. A
"pass-through" cross-connection is needed at all other nodes (intermediate
nodes) on the ring.
For the DDM-2000 OC-3/12 Multiplexer, cross-connections of both ring paths are
entered with a single command entry per shelf. This minimizes the possibility of
provisioning a circuit without a protection channel. A DDM-2000 OC-3 ring has 84
VT1.5 channels or 3 STS-1 channels. The OC-3 ring channels are always carried
within the 22-type OLIU circuit packs in the main 1 and main 2 slots. A DDM-2000
OC-12 ring has 336 VT1.5 channels or 12 STS-1 channels. The OC-12 ring
channels are always carried within the 24 or 29-type OLIU circuit packs in main 1
and main 2 slots. The VT1.5 ring channels are designated m-{sts#}-{vtg#}-
{vt#}. The STS-1 channels are designated m-{sts#}. In cross-connection
provisioning, there is no need to identify ring channels in main 1 different from
main 2 because both rings are always provisioned with the same information.
At the entry and exit points, the VT channels are cross-connected to the low-
speed ports (for example, {ls group}-{slot#}-{port# on slot}, a-7-
4). These are called "drop" connections. For example, the command ent-crs-
vt1:m-2-6-4,a-1-3 connects the third low-speed port associated with slot 1 of
low-speed group A to the fourth VT1.5 within the sixth VT group within the second
STS-1 of both rings. Similarly, for STS-1 channels, the command ent-crs-
sts1:m-2,a connects the DS3 or EC-1 port of function group A to the second
STS-1 of both rings.
At the intermediate nodes, a pass-through cross-connection establishes a cross-
connect path on both rings. Pass-through cross-connections are designated by
using the same VT or STS-1 ring channel twice in the cross-connect address. For
example, the single command ent-crs-vt1:m-2-6-4:m-2-6-4 connects a
pass-through cross-connection both to and from the fourth VT1.5 within the sixth
VT group within the second STS-1 of both the service and protection ring. Also
note that, unlike linear networks that require 22-type OLIUs in both main and fn-C
slots to create pass-through connections, ring pass-through cross-connections
are made directly between both main OLIUs.
Depending on local practice, work orders will normally identify the low-speed port
designations at the entry and exit points in the network and the TIDs of the NEs at
these points. The work order may also designate the VT1.5 or STS-1 ring channel
which will be used for this service. If the work order does not designate a ring
channel to use, use the command rtrv-crs-vt1; or rtrv-crs-sts1; to
identify all the ring channels that are currently unassigned. The work order also
may not designate all the other NEs on the ring that need to be provisioned with
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